1. Field of the Invention
The present invention relates generally to exercise machines, and is particularly concerned with a rigid arm pull down exercise machine for performing chin up and pull up type exercises.
2. Related Art
A free chin up or pull up exercise involves an overhead bar which the user grips with their hands and then pulls in order to raise or lower their body. This is an exercise which is difficult for many people to perform, and requires balance, coordination and strength for an exerciser to raise and lower their body while suspended by their hands. The exercise involves a multi-joint movement involving muscles in the upper and lower back as well as the biceps and forearm. Improper form by the exerciser, such as swinging, kicking the legs, arcing backwards or not tucking the head, can make the exercise more difficult, increase stress to the joints, or lead to injury.
The counter-balanced or assisted chin-up machine was developed in order to enable less conditioned exercisers to perform this basic exercise movement, and also in order to provide a safer chin up or pull up exercise. Some examples of machines for performing chin up/pull up exercises are U.S. Pat. No. 3,592,465 of Fulkerson, U.S. Pat. No. 3,707,285 of Martin, U.S. Pat. No. 4,111,414 of Roberts, U.S. Pat. No. 5,011,139 of Towley, U.S. Pat. No. 5,322,489 of Webb, U.S. Pat. No. 5,449,959 of Homes, and U.S. Pat. No. 5,540,639 of Potts. These machines use various types of load or resistance to counter-balance the user's body weight and assist them in performing the exercise. In order to perform an exercise, the user stands or kneels on the user support, engages the handles, and then pulls with their arms in order to raise their body, assisted by the counter-balanced user support. Fulkerson, Martin, Holmes, and Potts use a linear, vertical movement, requiring the user's head to pass the handles in order to complete the exercise movement. In order to avoid the user's head from striking the handle bar in completing this movement, Holmes and Potts provide separate right and left handles so that the user's head can pass between the handles. In Fulkerson and Martin, the user must move their head to avoid the straight, single piece chin bar, which is both awkward and dangerous. Additionally, these designs do not duplicate the natural arcuate motion of a free bar chin up exercise.
Webb has a user support platform for supporting a user in a kneeling position, and does provide a more natural, arcuate movement path, so that the user's head will pass in front of the gripping means. However, because of this movement, Webb cannot provide a neutral grip position. The arcing away from, and then back towards, the vertical centerline of the handles requires the hand/wrist position to change and track with the user position. A fixed, neutral position would cause strain on the wrists, causing them to bend at an unnatural angle. In Towley, the user support arcs towards the user engaging handles throughout the entire arcuate path, avoiding this problem. However, separate handles must be provided to avoid the user's head from making contact with the handle bar. In each of the above known designs, although the user support moves, it is not urged to do so by movement of an exercise arm. The only user engagement means are a handle bar or handles which are stationary and fixed in relation to the exercise machine main frame throughout the exercise. The amount of exercise resistance felt by the user can never be greater than the user's body weight, which may not provide enough resistance for advanced users. These machines are also quite large and awkward to use, as the exerciser must climb up steps to mount the machines and must blindly try to find the steps when stepping backwards off the machine. The machines are also relatively complex and expensive to manufacture.
U.S. Pat. No. 3,640,528 of Proctor is an example of a traditional cable lat pull down machine. It has a weight stack mounted for vertical displacement on a main frame, a stationary user support on the frame, and an overhead user engaging bar connected to the weight stack via cables and pulleys. In order to perform the exercise, the user grips the exercise bar while seated on the seat, and pulls the bar down to his or her chin. Because it is a single piece bar, the user must take care to avoid hitting their head with the bar as they pull it downwards, since it is attached to a free-swinging cable. The user must therefore be careful to apply an even force with each arm and to pull the bar in the correct exercise path in order to avoid possible injury.
In order to avoid the safety concerns of a free cable lat pull down, the rigid arm lat pull down exercise machine was developed. This exercise machine consists of a main frame, a stationary user support fixed to the main frame, an exercise arm or arms pivotally mounted on the main frame, and a resistive load associated with movement of the exercise arm. U.S. Pat. No. 5,050,873 of Jones, U.S. Pat. No. 5,562,577 of Nichols Sr., and U.S. Pat. No. 5,810,701 of Ellis are examples of rigid arm pull down exercise machines. These machines have exercise arms providing a converging exercise motion, traveling inward towards one another during their exercise path. Jones and Nichols have dual exercise arms for independent exercise movement while the exercise arms of Ellis are dependent. Jones, Nichols, and Ellis all provide weight receiving means or pegs for adding weight plates to vary the exercise resistance.
U.S. Pat. No. 5,263,914 of Simonson and U.S. Pat. No. 6,074,328 of Johnson show lat pull down machines that utilize a sliding, adjustable load to vary the resistance to the exercise arm. U.S. Pat. No. 5,749,813 of Domzalski shows a selectorized lat pull down machine which has an exercise arm assembly with user engaging means mounted to a first end and a pivotal connecting linkage attached to its second end. The load is connected to the exercise arm via the pivotal connecting linkage.
U.S. Pat. Nos. 5,447,480 and 5,549,530 of Fulks both describe multi-exercise machines which include a back supported lat pull down exercise. In both cases, the exercise arm is pivotally mounted on the main frame for bidirectional movement. In the first patent, a user support carriage is slidably mounted on the base of the frame to provide fixed adjustment points for the user support relative to the exercise arm. Other rigid arm lat pull down machines with a fixed user support are described in U.S. Pat. Nos. 5,437,589 and 5,967,954 of Habing, U.S. Pat. No. 5,597,375 of Simonson, U.S. Pat. No. 6,071,216 of Gianelli, and U.S. Pat. No. 6,394,937 of Voris.
These prior art lat pull down exercise machines are all subject to various disadvantages. In some cases, the user has to adjust their body position or tuck in their head to miss a single bar user engaging means, as in Fulkerson, Martin, and Proctor. Some of the machines are not easily accessible, particularly those with moving user support platforms such as Fulkerson, Martin, Towley, Webb, Holmes and Potts. These machines in general do not provide all the possible hand grip starting positions for different types of chin up/pull up exercises, and do not provide proper starting and finishing arm/hand positions. In the machines with pivoting exercise arms which travel in an arc, the arc motion is generally greater than that of the natural, free bar exercise motion, producing an exaggerated and unnatural exercise movement.